On Draining. 193 



ed up ; and is driven forward by a man in the same man- 

 ner("<). 



5. A sod-knife ( ' 4 7 ) is useful in setting out the trenches, 

 the workmen treading it in by the side of a line, five or six 

 inches deep. It is more expeditious, and easier to the work- 

 men, than the spade. 



6. The borer, or auger, used in draining, is very similar 

 to that employed in searching for coal, or other subterrane- 

 ous minerals ( I48 ). 



5. Modes of Draining applicable to different Soils, and the 

 Objects to which they are applicable. 



1. Clays. It is a subject of great controversy, to be af- 

 terwards discussed, (Chap. IV. Sect. 1. 1.) what is the 

 proper breadth of ridges, in a clayey soil, with a view to 

 drain it. The only point necessary to be here touched upon, 

 is, whether, in clays, the drains should be open, or covered. 

 In general, open drains are to be preferred, being less expen- 

 sive to form, more easily kept in order, and more certain in 

 their effect. At the same time, in some particular cases, 

 covered drains have succeeded. In the Duchy of Limberg, 

 they prefer having such drains in the furrows of strong land, 

 by which less ground is lost, and the soil is rendered at all 

 times accessible to culture ( I49 ). The celebrated Arbuth- 

 not, (who is characterised by Mr Arthur Young, as the best 

 farmer he ever met with, in the course of his long expe- 

 rience ( I5 ), practised that system near Mitcham in Surrey; 

 and an intelligent Scotch farmer, (Mr James Andrew, at 

 Tillylumb, near Perth), has carried the same plan into ef- 

 fect, with the greatest success. He was formerly at the mer- 

 cy of every season, and found none so dry, but that in a 

 certain degree he sustained some injury ; but since he has 

 adopted the plan of a hollow drain in every furrow, he can 

 plough at any time ; the seed can be put in, if there be but 

 a single dry day ; in the ordinary course of things he can 

 always rely upon a crop; and the soil being nearly of the 

 same quality, and in a similar state, the crop is always 

 equal ( l51 ). In the western districts of Scotland furrow 

 draining is extended to grass lands, greatly to the improve- 

 ment of the herbage. 



2. Loams. When loams are allowed to rest, they some- 

 times acquire a degree of cohesion little inferior to clay. 

 They generally absorb water rather freely, and after retain- 

 ing a proper quantity for vegetation, they allow the super- 



